I'm pleased to hear that you were able to figure out how to correct your scrolling gallery code from an existing thread on our forum.
Our system is configured to automatically generate a scrolling gallery image for each listing once, at the time the listing is posted or imported into our system. While I am not aware of any current technical problems that would cause the wrong image to be imported, if you were to change the header image in an active listing, it is expected that we would be unable to update the scrolling gallery image for the item automatically.
In the event you need your scrolling gallery images update to reflect the current header images in your eBay listings, please contact our customer support team by mousing over the “Help” tab and selecting the “File a Support Case” option and we can do that for you.
We do not currently have any plans to create a way for users to force these updates on their own, but we will treat your comments in that regard as a suggestion for future consideration. I hope this helps you know what to expect!